Chapter IV. Post-natal losses

Neonatal mortality
Preweaning mortality
Post-weaning mortality
References for chapter IV

One of the key indicators of the efficiency of a small ruminant production system is the degree to which lambs and kids survive to a marketable age and/or to a sustainable reproductive life. Low survival rates may be signs of serious problems in such a system; they may be, as Osuagwuh (1985) put it, indications of a very low standard of husbandry. They may also be among the major causes of a reduced rate of multiplication of animals and poor return to capital invested. Thus, knowledge of postnatal losses is a prerequisite for a good understanding of the production system of interest and to the adequate diagnosis of the related constraints.

While researchers in SSA are unanimous about the need to study and reduce postnatal losses in small ruminants, they fail to express these losses in standardized ways, which are necessary for proper understanding and comparisons. In the literature reviewed, mortality rates were expressed either on the basis of percentage of total animals born, total death, total death in the class and rarely as percentage of animals born alive. Information reported this way is incomplete, confusing and of little use, particularly in many cases when it does not allow the reader to calculate indicators of interest that are not presented by the author (also see footnote 5). Further, it is likely that, in many instances, stillbirths are included in postnatal death components. In this review, postnatal reproductive losses will refer to losses occurring from birth to 12 months of age and will entail neonatal death, preweaning and post-weaning mortalities. These losses will now be examined.

Neonatal mortality

Lamb neonatal mortality
Rid neonatal mortality

Neonatal mortality refers to death occurring within the first four weeks of the life of kids or lambs born alive (Dennis, 1970). It is the postnatal component of the perinatal death which also includes stillbirths. In this review, the term "neonatal period" specifically means first 30 days after birth and where possible, age specific mortalities within this period will be presented.

Lamb neonatal mortality

Estimates of neonatal lamb deaths in SSA are few. Under station management conditions in the humid zone of Nigeria, rates of 14.70 per cent of lambs born alive and 16.50 per cent of all lamb deaths were reported, respectively, by Otesile and Oduye (1983) and Otesile et al. (1983). Reports from other on-station studies indicated an estimates of 16.60 per cent in Ghana (Tuah et al., 1987) and a high contribution (63 per cent) of neonatal death to overall kid mortality in Cameroon (Ndamukong, 1985). At the village level, kid losses occurring within the first month of life accounted for 15.25 per cent of all lambs born alive in the semi-arid zone of Sudan (Wilson, 1976) and for 67.8 per cent of all deaths in the 0 to 5 month-age class in the highlands of Ethiopia (Wilson et al., 1985). The latter authors also estimated that of the mortality recorded between 0 and 5 months, 35.6 per cent occurred during the first day and 22 per cent from the second to the seventh days after birth.

Neonatal lamb death may be of either non-infectious or infectious origin. Hartley and Boyes (1955) and Alexander et al. (1959) cited by Tuah et al. (1987) recognized three categories of causes. These are starvation, dystocia and undiagnosed. Wiener et al. (1983), working in Scotland, recorded as many as 175 factors that they recognized as first, second and/or third causes of neonatal death. The authors (Wiener et al., 1983) also arranged these factors into eight broad groups of causes among which was a condition they termed "weakly lamb". Such a condition involves weak lamb at birth, underdevelopment, exposure, starvation in general and starvation due to maternal agalactia in particular. Whatever the causes, the incidence of neonatal death may be affected by predisposing (or secondary) factors such as birth weight, dam age, birth type, parity, sex of neonates, season of the year and parturition interval. After examining the main and secondary factors responsible for lamb neonatal deaths in the humid zone of Ghana, Tuah et al. (1987), concluded that starvation was the most important cause followed by pneumonia. The work of these authors (Tuah et al., 1987) is probably the best that can be found in published literature on lamb and kid neonatal mortality in SSA. Unfortunately, the number of observations presented was too small and the fate of lambs in the 3 to 30 day age class was not examined. In the semiarid zone of Mali, Traore (1985) found that lambs which died in the first week of life in agropastoral systems did so from "immaturity and subvitality", conditions which can reasonably fit into the "weakly lamb complex" since, as Wiener et al. (1983) put it, they converge in their effect of weakening the lamb and precipitating death. Under station management in the sub-humid zone of Togo, type of birth was found to account for 85.12 per cent of total variability in lamb mortality between birth and 5 days. More than 25 per cent of twins compared with 14.55 per cent of singles died within the above period (Abassa and Adeshola-Ishola, 1988). Under similar managerial conditions in the humid zone of Senegal, neonatal mortality was reported to be 75.5 per cent higher among twins than among singles (Fall et al., 1983). Certainly, poor survival of twin lambs is linked to their birth weights which are generally lower than those of singles. In general, however, whenever birth weights fall far below the average of the breed, both single and twin lambs suffer from higher than average mortality during the neonatal period. This agrees with the findings of Tuah et al. (1987) in Ghana, Abassa and Adeshola (1988) in Togo, Rombaut and Vlaenderen (1976) in Côte d'Ivoire. The study in Togo showed that 37.1 per cent of lambs weighing less than 1 kg died within the first five days of life while only 11.31 per cent mortality were recorded for the same period among those weighing between 1 and 1.5 kg. In the Côte d'Ivoire study, neonatal death toll under traditional management conditions was estimated at 57 and 12 per cent among lambs weighing respectively less than 1 kg and from 1 to 1.5 kg. This study also showed the adverse effect of shorter than average parturition intervals on survival of neonate lambs: 30 per cent of the lambs died when interval between births was less than 7 months compared with 20 per cent when this interval was greater than 7 months. The study, further, referred to the cause of this poor performance as "fatigue of the dams" and highlighted the negative effects of premature matings of young females on the birth weight and survival of their progenies. Finally, the study blamed the lack of basic herd management and particularly the notorious uncontrolled breeding which favours indiscriminate matings and related undesirable effects. In Ghana, Tuah et al. (1987) established that the highest mortality rates were in lambs born to 2 and 7 year old ewes and blamed inadequate management for the decreased survival. In Togo, the lowest death rates were recorded in lambs associated with second to fourth parities. Management can also contribute to higher than "normal" neonatal mortality rates when it allows lambs to be born during unfavourable seasons as shown by most studies quoted above. The above studies showed a tendency for lower than average survival rates in animals born during dry seasons in the semi-arid areas and wet seasons in the humid zones.

Rid neonatal mortality

As for lambs, little is published on kid neonatal mortality in SSA though there are some indications that early death may account for a substantial proportion of postnatal losses. On-station studies by El-Naim (1979) in the semi-arid zone of Sudan showed that up to 74.4 per cent of preweaning casualties corresponding to 66.7 per cent of total post-natal death occurred during the first week of life in Sudan Nubian kids born alive. In the humid zone of Nigeria, 56.1 per cent of the mortality observed from 0 to 3 months of age happened during the first day of life in station-managed WAD kids (Osuagwuh and Akpokodje, 1981). The proportion of WAD kids which died was not revealed nor was the specific neonatal loss reported. Conversely, it was disclosed that 89.8 per cent of total deaths of Sudan Nubian kids born alive were neonatal and that 32 per cent of these kids died during the first week of life. Of all deaths under humid zone and village management conditions, 61 per cent were reported to have occurred in less than one-month old WAD kids and lambs in Nigeria (Mack, 1983) and 16.6 per cent in one week old Landim kids in Mozambique (Makinnon, 1985). Under these same conditions, 76.42 per cent of kids which died from birth to 4 months of age were reported to be in the 0-30 day age group (Ndamukong, 1985).

From the preceding, it can be seen that most published data on kid neonatal death were calculated on the basis of percentage of total deaths. The number and proportion of kids born alive which died during the neonatal period were generally not revealed ⁴. Chances are that high proportions of total preweaning deaths occur during this period. Perhaps, one of the greatest constraints to the adequate assessment of the potentially high neonatal death is the paucity of data coupled with the improper reporting of the available information.

⁴ The reason why this is needed is specified in the introductory notes of this chapter. Also, see footnote 5.

The main causes of kid neonatal death worldwide are similar to those listed earlier for lamb neonatal mortality. The condition involving weak kids at birth, underdevelopment, exposure and starvation will be referred to as "weakly kid syndrome or complex". In SSA, most causes of early deaths, particularly in the village flocks, are unknown. Further, most reports failed to address age specific causes of death within the preweaning period. Such a situation limits the clear assessment of the specific reasons for neonatal kid death.

A number of reports have placed emphasis on secondary factors which trigger the pathologies and/or cause death tolls to increase. Among these factors are birth weight-birth type combinations, parity and season of birth. That birth weight is by far the most critical of all in view of its adverse effect on kid survival is overwhelmingly recognized in SSA (Sacker and Trail, 1966; Kyomo, 1978; Nwody, 1979; Osuagwuh and Akpokodje, 1981; Murayi et al., 1987). El-Naim (1979) reported that low birth weights due to large litter sizes were the cause of 64.4 per cent of deaths occurring during the first month of life in kids raised under station management and semi-arid zone conditions in Sudan. In the humid zone, Osuagwuh and Akpokodje (1981) in Nigeria, observed that, of station managed kids which died the first day of their life, 50.7 per cent, 29.0 per cent and 20.3 per cent were among triplets, twins and singles, respectively. Under similar management conditions in the sub-humid zone of Malawi, 35.7 per cent of twins were reported to have died within the first week of life while death of only 4.34 per cent of singles was recorded during the same period (Reynolds, 1979). As stated earlier for lambs, the lighter weight of twin kids as compared with singles makes them more vulnerable. There are, however, instances where single kids may be highly susceptible as well. Though such instances may be rare in SSA, earlier studies by Sacker and Trail (1966) revealed that mortalities in heavier single East African kids were high, particularly when these kids were from first kidder dams. In general, first kidders and/or multiple births are the most important sources of low birth weights which in turn cause general weakness and starvation that lead to death. Weak kids are also more prone to infections and predator attacks than stronger ones.

Season of birth, a generally uncontrolled factor in SSA, is another very important contributing cause of early death in the prevailing traditional production systems of the region. El-Naim (1979) in the semi-arid zone of Sudan showed that neonatal mortality rates were variable between seasons and that higher rates were obtained during the rainy seasons where high incidence of low birth weights and coccidiosis prevailed. Oppong and Yebuah (1981), working in the sub-humid zone of Ghana, pointed out that frequency of kid mortality was affected by rainfall and that during the rainy season the weak and young kids abandoned by their dams may die either from starvation or pneumonia. More details on the seasonal effects on kid death will be given in the preweaning mortality section.

Of paramount importance is that causes of death also tend to be age specific. Traore (1985) identified two vulnerable "periods of pathological crisis" in the early life of kids raised under village conditions in the semi-arid zone of Mali. From 1 to 7 days of life "weakly kid syndrome" was the major cause of death. During the second period which was from 8 to 30 days after birth, deaths were due to afflictions with complex and non-specified etiology (eg., pneumopathies, diarrhoea, subvitality). Specific and easily identifiable pathologies such as pasteurellosis and PPR could only be sorted out during the second period which was known to extend from 3 to 5 months of age.

Overall, it can be concluded that deaths of neonate kids and lambs have not been extensively investigated in SSA. Most studies were carried out in the humid zones. Due to lack of data presented, it is difficult to draw patterns by management system and species and make comparisons within and between ecozones. Most estimates were on percentage of total deaths basis. Thus, the number ⁵ and proportion of kids and lambs born which died during the neonatal period were generally unknown. Judged from the available albeit limited information, neonatal mortality rate (i.e. from 0-30 days) may generally be considered above 20 per cent (probably 20-30 per cent) of kids and lambs born alive and may account for more than 70 to 80 per cent of preweaning deaths. The proportion of neonatal death occurring within the first week of kid and lamb life in SSA may be substantial as well. This is expected since such mortality is generally reported to be relatively high elsewhere even under better management conditions (Highs and Jury, 1970 cited in Meyer and Clarke, 1978). In this connection, it is interesting to note that Blood et al. (1981) quoted in Tuah et al. (1987) estimated the proportion of preweaning mortality that is found in the first few days of life at 70 to 80 per cent agreeing with Willingham et al. (1986) who found that in Texas (USA), 73 per cent of lamb preweaning losses were in the first few weeks of life. Most causes of these losses are generally either unknown, not investigated or not reported. However, "weakly lamb/kid syndrome,, seems to be the single most important cause of death. Pneumonia, mentioned on a few occasions, may be the next cause. The most important predisposing factor is birth weight or birth weight-litter size complex followed by dam age, season of birth and parturition interval. Survival seems to be higher in neonates born during rainy seasons in the semi-arid area and dry seasons in the humid zones.

⁵ The need to have the number of lambs and kids dying is consistent with the fact that without it, the proportions of age-specific deaths of interest which are missing in most published documents cannot be calculated.

Preweaning mortality

Estimates of kid preweaning mortality
Estimates of lamb preweaning mortality
Causes of kid preweaning mortality
Causes of lamb preweaning mortality

Preweaning mortality refers to death occurring between birth and weaning of kids or lambs born alive. It includes neonatal deaths. Studies carried out in SSA indicate that man induced weaning as a management device is not practiced in the traditional systems of production. Kids and lambs run with their dams until after the milk production of the latter has come to an end. Further, because most local breeds are poor milk producers, expectations are that the maternal milk provision will stop before or at the time the suckling kids/lambs are 5 months old. This situation is not specific for traditionally managed flocks; it is also found under station management conditions where the research objective is to maintain animals under conditions which are as close as possible to those characterizing on-farm traditional management. While the reason for the lack of imposed weaning of kids and lambs whose dams provide no milk for household consumption and sale is not quite understood, literature reveals that where weaning takes place as a management device, it generally does so when lambs and kids are 3 or 4 months of age. In this section, therefore, age at weaning will be from 3 to 5 months both at station and village levels and no attempt will be made to separate preweaning death rates by ages. The question as to wether stillbirths are included in preweaning mortalities found in published reports will remain unanswered in the section as these reports generally do not specify the life/death status at birth of the animals.

Estimates of kid preweaning mortality

Table 4.1 shows available estimates for kid preweaning death in SSA. Overall, they vary from 14.9 to 55 per cent under station management conditions and 19.6 to 43.5 per cent at village level. In the humid and sub-humid zones, the lowest estimate at the station level (23 per cent) was obtained for Tanzanian kids in Tanzania (Kyomo, 1978) and the highest (55 per cent) for WAD in Ghana (Oppong and Yebuah, 1981). At the village level in these zones, extreme values are 19.6 per cent for WAD in Nigeria (Most et al., 1982) and 43.5 per cent for Newala kids in Tanzania (Hendy, 1980).

In the semi-arid area, estimates vary from 14.9 per cent for Boer x Indigenous crosses in Zimbabwe (Khombe, 1985) to more than 40 per cent for Nubian kids in Sudan (El-Naim, 1979). No other estimate is available for the highlands apart from the 26.3 per cent reported in Rwanda by Murayi et al. (1987).

Information on the contribution of preweaning mortality to total death is limited (table 4). Available records indicate, however, that in the humid and sub-humid zones, this contribution may be substantial as it was estimated at 72.10 per cent in Ghana (Oppong and Yebuah, 1981), 50 per cent in Senegal (Faugère et al., 1988), and 75.8 and 78 per cent in Ghana (Yebuah, 1975 cited in Dankwa, 1976 and Dankwa, 1976, respectively).

It appears that preweaning mortality among kids in SSA is variable, that published observations are limited in the humid, sub-humid and semi-arid zones, virtually inexistent in the highlands. It can be concluded that at least 20-40 per cent of kids may be expected to die before weaning under station conditions of SSA. Under these same conditions, it is possible that the death toll amounts to 30-50 per cent in humid and sub-humid zones and 20-40 per cent in the semi-arid area. Lower preweaning rates were published for kids under village management than under station conditions. This however, except perhaps in some state or parastatal farms, does not seem to be conceivable in the face of lack of general management and data recording scheme characterizing the production systems in the family sector. Mortality rates reported for the sector may have been underestimated as research under traditional systems faces more constraints and requires longer investigations and larger sample sizes for the results to be meaningful than investigations on station. Further, it is not clear whether the on-station death rates examined here should be considered as indicative of decreased viability of native goat breeds known as "freedom seekers" when they are moved from their natural production system where a high degree of freedom is allowed to the restricted station management environment where such a freedom is limited. Nevertheless, until the interactive effects of goat behaviour and managerial conditions on kid mortality are clearly determined, it is conceivable to consider that the true estimate of preweaning kid loss in traditionally managed flocks is higher than that found under station management conditions. The contribution of preweaning death to total mortality in the humid and sub-humid zones could be expected to be high, perhaps 50 to 80 per cent.

Estimates of lamb preweaning mortality

Available estimates for lamb preweaning mortality in SSA are collated in table 4.2. Overall, they range from 10 per cent for WAD lambs in the humid zone of Côte d'Ivoire (Ginisty, 1977) to 44 per cent for Uda lambs in the sub-humid zone of Nigeria (Adu and Brinckan, 1978 cited in Osuagwuh, 1985). In the semi-arid zone most rates are between 19.6 per cent for Peul lambs in Senegal (Sow et al., 1988) and 32.10 per cent for Masai lambs in Kenya (Wilson et al., 1985). An extreme paucity of information is observed both at station and village levels of the highlands and at village level of humid, sub-humid and semiarid areas.

As for the contribution of preweaning mortality to total death, it may be quite variable. For WAD lamb in humid zone, Oppong (1973), Dankwa (1976) and Otesile et al. (1982) estimated it at 32.1, 47.8 and 18.8 per cent, respectively. Ndiaye (1992) also reported that more than 40 per cent of the deaths recorded between birth and 12 months of age in traditionally managed lambs (and also in kids) in the humid zone of Senegal, occurred during the 0-3 month age period. In the semi-arid zone of Mali, Traore (1985) found that more than 60 per cent of lamb and kid deaths were from birth to weaning.

It could be concluded that under station conditions, at least 20-30 per cent of lambs may die between birth and weaning in humid, sub-humid and semi-arid zones of SSA. As stated earlier, casualties are expected to be substantially higher at the family sector level than at the research stations. From the limited data presented, it is difficult to assess the magnitude of the contribution of preweaning mortality to the total lamb death. The review of the overall available estimates tends to indicate a lower preweaning fatality in lambs than in kids. To this end, chances are that the above contribution is lower than that found for kid preweaning death.

Causes of kid preweaning mortality

Available published data on the causes of kid preweaning mortality are collated in table 4.3. Overall, the most common cause of death is pneumonia (of various origins) whose contribution to the preweaning mortality ranges from 11.9 to 51.8 per cent with the lowest value obtained for WAD kids under station management conditions in Nigeria (Osuagwuh and Akpokodje, 1981) and the highest for Sahel kids in Mali (Traore, 1985). "Weakly kid syndrome" seems to be the second most reported cause followed by parasitic infestation and unknown causes. The syndrome's contribution to the preweaning death may be very variable as it goes from 3 per cent for station managed kids in Nigeria (Osuagwuh and Akpokodje, 1981) to 64.8 per cent for Tanzanian kids also station managed in Tanzania (Kyomo, 1978). The unknown (i.e., mortality of unknown etiology) found in only a few reports may have contributed highly as substantiated in Oppong and Yebuah (1981), Wilson et al. (1984), Traore (1985). A proportion as high as 44.4 per cent of preweaning mortality was ascribed to unknown causes in traditionally managed East African kids of Kenya (Wilson et al., 1984).

Due to lack of available data, it is difficult to make comparisons between and within ecozones. It is also difficult to rank the major causes according to the magnitude of their contribution to the total loss. However, pneumonia, the most commonly reported condition, also appears to be the first kid killer during the preweaning period in view of the evidence presented for the semi-arid zone by Traore (1985) and Wilson et al. (1984) in Mali, Madjit (1980) in Chad and for the humid or sub-humid zone in Ghana by Vohradsky (1966 cited in Oppong and Yebuah, 1981), Oppong and Yebuah (1981), Dankwa (1976), in Nigeria by Osuagwuh and Akpokodje (1981), Bayer (1982), Otesile et al. (1983), Osuagwuh (1984 cited in Osuagwuh, 1985), and in Kenya by Angwenyi and Bebe (1989). Traore (1985) found that PPR, pasteurellosis and other pneumopathies induced afflications accounted for more than 50 per cent of preweaning mortality in the semi-arid zone of Mali. The condition may occur in the form of broncho-pneumonia, suppurative pneumonia and/or fibrinous pneumonia (Otesile et al., 1983) and can be, among other things, of PPR and/or pasteurellosis origins. Related death is recorded during rainy seasons in humid and sub-humid zones (Wilson et al., 1984; Oppong and Yebuah, 1981; Osuagwuh, 1985; Opasina, 1985), both rainy and dry seasons in semi-arid zone (Traore, 1985) and in humid areas (Otesile et al., 1983; Faugère et al., 1988). Reports generally agree, however, that the death toll is highest during the rainy or cool season of the humid and sub-humid zones and during the cool dry season of the semi-arid zone. Traore (1985) reported that the fear of devastating pasteurellosis during this cool dry season creates a "real psychosis" among small stockholders in the semi-arid zone of Mali.

While pneumopathies seem to emerge easily as the number one kid killer, it is not quite clear in the literature which of the two remaining major conditions, helminthiasis and "weakly kid", should be ranked as the second most important cause of death. Kyomo (1978) found general weakness to be the main reason for Tanzanian kid death, Faugère et al. (1988) ranked underdevelopment as the first WAD kid killer, Traore (1985) and Oppong and Yebuah (1981) showed that weak neonate/starvation complex ranked second after pneumonia in causing death in Sahel type and WAD kids, respectively. Therefore, it is likely that the "weakly kid syndrome" is the second most important cause of preweaning mortality among kids in SSA. It may well be that in many cases, this syndrome represents the first most important hazard as evidenced by on-station investigations in sub-humid zone of Tanzania where nearly 65 per cent of preweaning mortality were due to general weakness (Kyomo, 1978) and on-farm research in the humid zone of Senegal, where underdevelopment was by far the most important cause of death during the first 3 months of the kid's life and was responsible for 2/3 of death occurring within the first month after birth Faugère et al., 1988). It is suggested that maternal agalactia, ascribed to poor nutrition of the dams, a consequence of poor rainfall, might have been one of the major predisposing factors in the semi-arid area as well as in the humid zones. Not surprisingly, Oppong and Yebuah (1981) have observed that starvation of kids in sub-humid zone of Ghana occurs when the rain fails.

Among other predisposing factors is the birth type which has a tremendous influence on kid survival through its effect on birth weight. Mayer and Clark (1978) observed that twins of the same birth weight as singles are more susceptible to mismothering and hence to starvation losses than the latter. However, it is overwhelmingly recognized that in SSA, multiple birth is generally accompanied by low birth weight which, in turn, results in higher mortalities in twins and triplets than in singles (Oppong and Yebuah, 1981; Osuagwuh, 1985; Traore, 1985). Oppong and Yebuah (1981) suggested that since the WAD goat is not a dairy animal, does are unlikely to he able to raise more than one kid successfully under poor nutrition conditions. It is probably in the semi-arid area that increasing litter size leads to more problems as substantiated by Traore (1985), who found that most conditions of preweaning death in Mali were in twins and triplets and that multiple birth contributed a great deal to high prevalence of infectious diseases.

Birth weight is not only affected by birth type; it may also be largely influenced by sex, breed and parity/dam age. Osuagwuh and Akpokodje (1981) in the humid zone, and Oppong and Yebuah (1981) in the sub-humid zone agreed on the prevalence of higher death rates among female than male kids raised under station management conditions. However, it was found that viability of traditionally managed kids in the sub-humid zone of Tanzania (Hendy, 1980), humid zone of Nigeria (Opasina, 1985) and semiarid zone of Kenya, Mali and Sudan (Wilson, 1984) was either unaffected by sex or was lower in the male than in the female kids. While the reasons for this variation are yet to be documented, Oppong and Yebuah (1981), after observing that 55 per cent of the kids which died were females, lamented that such a situation is a setback to the rapid multiplication of the flock. It Could be that breed and management interactions play an important role in the variation of mortality rate through birth weight.

The existing positive correlation between birth weight of the progeny and weight of the dam is also an important factor to consider together with dam age or parity. Does are lighter at their first kidding than at their subsequent parturitions, a situation which along with their inexperience, invariably causes high mortality among their kids (Nwodi, 1979). Wilson et al. (1984), working in the semi-arid zone, found that the most important single secondary variable influencing kid preweaning death was parity; they estimated the preweaning death rates among first, second and third parity kids to be 47.9, 38.8, 31.4 per cent, respectively, in Mali and 43.7 per cent, 21.6 per cent, 12.3 per cent, respectively, in Sudan.

It would appear that available data on causes of kid preweaning mortality in SSA are limited, that most investigations were limited to research stations and that little or nothing is known for the highlands. Pneumopathies appear to be the first cause of kid preweaning death in semiarid, humid and sub-humid zones. They may occur in any season but are more devastating in the cool dry season of semi-arid zone and rainy season of humid and sub-humid zones. The second most important cause of preweaning death may be the "weakly kid complex" followed by helminthiasis. The former may be more important during the dry season particularly in the hot dry season of semi-arid zone and the latter in the rainy season. Birth type/birth weight combinations, parity and sex seem to be the most important contributing secondary factors in that order.

Causes of lamb preweaning mortality

The main causes found in the literature for preweaning mortality in sheep of SSA are shown in Table 4.4. Of the available information, 82.6 per cent were published from research stations, 17.4 per cent from the family sector, 43.5 per cent from humid zone, 30.4 per cent from the sub-humid zone, 21.7 per cent from the semiarid zone and 4.4 per cent from the highland areas. The main causes can be partitioned into four groups. These are "weakly lamb syndrome", pneumopathies and parasitic infestations and others. Pneumopathies encompass pneumonia of all origins including Peste des Petits Ruminants (PPR) while parasitic infestations are essentially made up of haemonchosis, coccidiosis and tapeworm infestation. Others in this section includes diarrhoea of various origins and pox. From the limited data available, indications are that "weakly lamb complex" may have accounted for 2 to 35 per cent of preweaning death, pneumopathies for 2.8 to 60 per cent and parasitic infections for 0.6 to 10.1 per cent.

Studies in the humid and sub-humid zones indicate that substantial proportions of deaths occurring from 0 to 12 months, were in the preweaning period. These proportions amounted to 53.3, 41.2 and 41.2 per cent for pneumopathies, tapeworms and enteritis due to other parasites, respectively, at Nungua research station in Ghana (Oppong, 1973). At the agricultural research station of Legon also in Ghana (Dankwa, 1976) 91.5, 73.5, 38.4, 60.3 per cent were accounted for by starvation, pneumopathies, tapeworms and other parasitic infections, respectively. Otesile et al. (1982) recorded 44.4 per cent pneumopathies and 34.5 per cent parasitic infections at the University of Ibadan teaching and research station in Nigeria. The data presented by the latter authors also showed that 50 per cent of the mortality due to parasitic infections in the 0-3 month age group were from haemonahosis while 32.1 per cent of those ascribed to pneumopathies were due to PPR. Reports, however, indicate that in traditionally managed flocks in the humid zone of Senegal, PPR has not brought about any casualty in the 0-3 month group and that the most critical condition in that group was diarrhoea which accounted for 50 per cent of all deaths occurring in the preweaning period Faugère et al., 1988). In the semi-arid zone of Senegal, diarrhoea induced deaths in village flocks also seemed to concentrate in the 0-3 month old age group as 5.2 per cent mortality was found between 0 and 3 months, 2.1 per cent between 4 and 12 months and 0.1 per cent between 1 and 7 years of age Faugère et al., 1989). In these flocks deaths ascribed to pneumopathies in general and PPR in particular were said to be negligible but those due to sheep pox in the O. to 3 month old age class amounted to 18.2 per cent. Elsewhere, in the semi-arid zone of Mali, traditionally managed lambs were also reported to have suffered substantial casualties due to pox (Traore, 1985). The author found that 36.7 per cent of preweaning deaths were due to pox while 23.3, 10 and 8.3 per cent were ascribed to "weakly lamb", pneumopathies and diarrhoea, respectively.

Perhaps, one of the most important aspects of the studies related to causes of lamb and kid deaths in SSA is the high frequency of undiagnosed cases categorized in what is termed as unknown. Losses due to this factor may stand high as shown by Peacock (1982) in Kenya, Traore (1985) in Mali, Faugère et al. (1988) in Senegal.

Among the predisposing factors of preweaning death are premature and indiscriminate mating of replacement females, season, type of birth, birth weight, age at first parturition, parturition interval, and particularly its role in the occurrence of dam's fatigue, and parity. Some of these have been focused on in the earlier discussions in relation to their effects on neonatal mortality. While these discussions still hold valid in the present section, evidence was presented which suggests that in the semi-arid zone, losses due to pneumopathies, pox and malnutrition prevailed in the dry cool and hot seasons in Mali (Traore, 1985), while the main cause of death in the dry cool season in Burkina Faso was found to be pneumopathies (Bourzat, 1980). In the humid zone of Senegal, Faugère et al. (1988) found that deaths due to pneumonia conditions in traditionally managed WAD lambs were limited to dry seasons with the maximum toll occurring in the cool dry season. Oppong (1973), however, found that most WAD lambs which died from these conditions in the sub-humid zone of Ghana, did so during the rainy season which was also referred to as the period of highest total mortality. The latter author acknowledged that death from pneumonia "was usually within 24 hours of the animal been caught in the rain". This is in agreement with the observation of van Vlaenderen, (1985) working with village flocks in Togo, who observed the very high mortality recorded during the wet season "was due to the rain which can cause pneumonia". Similar findings were highlighted by Fall et al. (1983) in Senegal and Abassa and Adeshola-Ishola (1988) in Togo who both observed that lambs under station management conditions and born in the rainy season suffered heavier casualties than those born in dry season. Fall et al. (1983) estimated the increase in mortality at 1.3 per cent from 3 days of age up to weaning for each additional 100 mm of rainfall and Van Vlaenderen (1985) found that more than 80 per cent of lamb casualties took place in the second half of the rainy season. It is during such a season that challenge from infective agents is highest and that death from parasitic gastroenteritis, mainly haemonchosis, occurs. Certainly, the decades old observation by Beal (1929) cited in Oppong (1973) that Haemonchus cortortus is "the curse of sheep and goat breeding" in Ghana still remains true in the humid zones of SSA. In connection with this, the suggestion by Otesile and et al. (1982) could not be more accurate when they pointed out that "in part of the humid tropic such as in southern Nigeria where the acquisition of large areas of land for farming is difficult and the environment favours rapid build up of the parasite, the cost of an efficient prophylaxis regime will be prohibitive".

It would appear that during the preweaning period, the main causes of lamb death in SSA are pneumopathies, "weakly lamb syndrome" and parasitic infections. The most important of these infections was haemonchosis. Here again available information is limited, making it difficult to produce useful comparisons between and within ecozones. Most data were published for the humid and sub-humid zones and were from research stations. In these zones, pneumonia appears to be the most important killer in the preweaning period followed by parasitic infestations and "weakly lamb syndrome". In the semiarid zone, available information suggested that either weakly lamb syndrome" or pox prevail as first deadly condition, followed by diarrhoea of various origins and pneumopathies. The latter can occur during any season of the year but the cool dry season in the semi-arid zone and the rainy season in the humid and sub-humid areas are periods when the lambs are most vulnerable. Death from parasitism particularly haemonchosis is highest during rainy seasons in the humid and sub-humid zones. Though little was provided in the literature regarding the seasonality of "weakly lamb-syndrome", chances are that this condition occurs all year round throughout SSA with the predisposing factors being dry season (particularly in the semi-arid zone), premature and indiscriminate mating of the replacement females, fatigue of dam due to short parturition intervals, lower than average birth weight and multiple birth.

Post-weaning mortality

Estimates of post-weaning mortality
Causes of post-weaning mortality

In the second chapter of this review, female progenies are assumed to be bred for the first time at an age that is less than or equal to 12 months. This implies that post-weaning mortality, in relation to reproductive losses in SSA's small ruminants is to refer, here, to death occurring between weaning and 12 months of age of kids or lambs. Published data on such death are generally scanty, a situation which will limit the scope of the discussions in this section.

Estimates of post-weaning mortality

Expressed on percentage of total animal basis, post-weaning mortality was 19.4 per cent for WAD lambs raised under station management conditions in the humid zone of Senegal (Fall et al., 1983) and 15 per cent for traditionally managed Newala kids in the Tanzanian sub-humid zone (Hendy, 1980). Their contribution to total death is not negligible as it was estimated at 30.2 per cent (Most et al., 1982) and 41.5 per cent (Opasina, 1983) for on-farm WAD kids in Nigeria, 16.2 per cent for station-managed WAD kids at Legon in Ghana (Oppong and Yebuah, 1981) and 43.9 per cent for WAD lambs also station managed in Nigeria (Otesile et al., 1983). Faugère et al. (1988) found that most village kid deaths in the humid zone of Senegal were in the period following weaning and that 50 per cent of these were between 3 and 7 months. Earlier investigations at the Legon university research station in Ghana (Dankwa, 1976) indicated that 24 per cent of the total deaths were occurred during the post-weaning period for WAD lambs and 11.1 per cent for WAD kids. These investigations also indicated that of the total mortality from birth to 12 months of age, 34.1 per cent were in the post-weaning period for lambs and 12.8 per cent for kids. Studies in Nigeria (Otesile et al., 1983) showed that up to 54.1 per cent of casualties recorded during the first 12 months in the life of kids were between 4 and 12 months. It has also been shown that of the total deaths recorded from birth to 11 months of age in WAD lambs, 66.1 per cent in Nigeria (Otesile et al., 1982) and 57.4 per cent in Ghana (Oppong, 1973) occurred between 4 and 11 months.

Causes of post-weaning mortality

Causes of post-weaning kid mortality found in published reports are mainly pneumopathies, particularly Peste des Petits Ruminants (PPR) origin, parasitic infections and bacterial enteritis. Pneumonia was reported to have been responsible for 32.9 per cent of deaths occurring between 3 and 12 months of age in station managed kids in the sub-humid zone of Ghana, parasitic gastro-enteritis (PGE) for 15.2 per cent and starvation for 1.3 per cent (Oppong and Yebuah, 1981). At the University of Ibadan farm located in the humid zone of Nigeria, pneumonia, helminthiasis and bacterial enteritis accounted for 41.0, 38.5 and 15.4 per cent respectively, of the deaths occurring from 4 to 12 months in the WAD kids (Otesile et al., 1983). Pneumonia was also found to be the most important cause of post-weaning death in WAD kids of 4 to 12 months of age at the University of Legon Research Station in the sub-humid zone of Ghana (Dankwa, 1976). It contributed 28.9 per cent of such deaths and was followed by PGE (17.8 per cent), heartwater (8.9 per cent) and starvation (2.2 per cent).

Among the major causes of pneumonia, PPR is by far the most important hazard in view of its related heavy economic losses limiting caprine production in West-Africa (Nduaka and Ihemelandu, 1973; Bourdin and Doutre, 1973; Abegunde et al., 1980 all cited in Opasina, 1979; and Akerejola et al., 1979). In Nigeria, Opasina (1983) found that the proportions of traditionally managed kids lost to PPR in the 4 to 8 month age group were highest 61.9 per cent in the humid forest and 56.1 per cent in the derived savanna when compared to those recorded in the 8 to 12 month age group (39.1 per cent in the humid forest and 33.3 per cent in the derived savanna). This may be an indication that goats are more vulnerable to PPR challenge at 4 to 8 months of age than during subsequent months. However, Faugère et al. (1988) suggested that most PPR induced death which occurred in village managed kids in the humid zone of Senegal did so between 3 and 24 months of age and that immunity to the condition probably takes long time to become established in goats. The above findings together with the observation of Opasina (1985) that PPR, known to be common in the rainy season, can now occur in the form of outbreaks in any season, demonstrate that the disease is probably one of the most alarming sources of risk associated with goat production at least in the humid and sub-humid areas of SSA.

Helminthiasis, and particularly haemonchosis which appears in most of the above humid/sub-humid zone data as the second kid killer after the pneumopathies has been the subject of many investigations (FAO, 1966; Fayibi, 1973; Kuil, 1973 all cited in Ndamukong et al., 1987; and Akerejola et al., 1979). Schillhorn van Veen (1982) cited in Ndamukong et al. (1987) referred to the humid zone goat as "a walking zoo" for its multitude of parasites. This statement was further substantiated by the latter authors, who found in a single goat, at autopsy in Bamenda (Cameroon), a haemonchus burden of more than 5,000 adult worms, when it was thought that sheep did not tolerate more than 2,500.

The major reasons for lamb mortality during the post weaning period have some degree of similarities with those reported for kids during the same period. At Nungua research station in the sub-humid zone of Ghana, pneumonia was found to be responsible for 28.4 per cent of total WAD lamb death occurring from 4 to 11 months of age thus competing with tapeworms (29.3 per cent) and followed by chemical poisoning (11.0 per cent) and other parasitic infections particularly of haemonchosis origin (10.0 per cent) (Oppong, 1973). Dankwa (1976), at Legon Research Station in Ghana, found that 20.9, 19.2 and 10.7 per cent of WAD lamb death between 4 and 12 months of age were ascribed to pneumonia, tapeworm infestation and heartwater respectively. Under humid conditions in Nigeria, 29.9, 17.9, 12.8 and 8.5 per cent of deaths occurring between 4 and 12 month of age in station managed lambs were said to be due to pneumonia, haemonchosis bacterial enteritis and starvation (Otesile et al., 1982) respectively. PPR, as source of pneumopathies, was said to have caused most deaths in the 3 to 12 month age group, the associated casualty rate being half of that found in kids Faugère et al., 1988). The latter authors indicated that lambs not only were protected by colostrum antibodies (e.g. no death was recorded from 0 to 3 months of age) but immunity was also developed earlier in sheep than goats. They also indicated that the diarrhoea which killed nearly half of the lambs before weaning (0-4 months) was less devastating during the post-weaning period and had no effect on adults over 3 years of age.

Sheep seem to have a lower tolerance of helminths than goats (Ndamukong, 1987). Their nutritional behaviour, e.g. sheep are less inclined to browse than goats, increases their risks of acquiring more pasture transmitted parasite infestations than goats (Anderson and Christofferson, 1973 cited in Ndamukong et al., 1987). Fascioliasis which is now believed to cause high mortalities among small ruminants in many areas of SSA, particularly in the highlands of Ethiopia, appears to be more harmful in sheep than in goats. Unfortunately, estimates of death rates by specific age of interest (e.g. preweaning, post weaning, after 12 month of age) due to the condition are lacking. It was estimated that 45.7 per cent of Ethiopian Menz type sheep which died between 7 and 50 months of age did so from this condition (Njau et al., 1988). Heavy mortalities due to liver flukes were also observed occasionally in sheep and goats grazing swampy or temporarily flooded areas in Nigeria (Akerejola et al., 1979). This agrees with earlier reports on goat death along the Yobe river (Henderson, 1937) cited in Akerejola et al., 1979) and on the prevalence of sheep infestations in Zaria (Kuil, 1972). In the agropastoral irrigated rice production area of the semiarid zone of Mali, Soumaila (1984) reported that, in general, fascioliasis which had little effect on goat survival, was the first sheep killer. The infestation rate was said to vary from 26.7 per cent at the end of the dry season to 42.1 per cent at the end of the rainy season in sheep, 8.3 to 12.3 per cent in goats and 32.6 to 66.7 per cent in cattle. In northern Nigeria, the prevalence rate of Fasciola gigantica infection was estimated at 64.4 per cent in cattle, 40.8 per cent in sheep and 17.6 per cent in goats with the highest incidence occurring during and directly after the rainy season, and with no significant difference between young and old animals (Schillhorn van Veen et al., 1980).

It appears that lamb/kid post-weaning mortality has not been under abundant investigations in SSA. The available published reports were mostly concerned with the humid and sub-humid zones. Losses found in these zones are high for both goats and sheep and chances are that they account for at least 20 to 40 per cent of total death occurring from birth to 12 month of age in kids and lambs of SSA in view of the high contribution of post-weaning mortality to the total death shown above and that of preweaning loss presented earlier. There can be no doubt that the highest kid/lamb post-natal mortality occurs in the 0 to 12 month age group of small ruminants in SSA. This is also in agreement with many authors such as Dumas and Raymond (1975), Dumas et al. (1977), Gerbaldi (1978), Vallerand and Branckaert (1975), Dumas, 1975, Jooste, 1974; Faugère et al., 1989; Faugère et al., 1988; Dankwa, 1976; Oppong and Yebuah, 1981). Pneumopathies of various origins are the undisputed first killer of kids and lambs. Among these origins is PPR, which was found to be one of the key constraints to goat and sheep production. It can occur any time of the year, causes heavier casualties in kids than in lambs with the former being critically vulnerable for a longer period of time than the latter. The second major killer disease was parasitic infestation with haemonchosis representing the prime hazard. Sheep seem to be less tolerant to Haemonahus sp. and more prone to tapeworm infestations than goats. As expected, starvation, a component of "Weakly kid/lamb complex" was found to have a negligible effect on survival at the post-weaning stage of life. Fascioliasis in humid, swampy, flooded or irrigated areas and in the highlands may be considered as a great threat to sheep production in SSA, mostly on the accounts of its heavy casualties. The possibility that Fasiola sp could be associated with Clostridium oedematiens and cause a serious havoc in the flocks in SSA just as it is already established elsewhere (Turner, 1930 cited in Ogunrinade and Adegoke, 1982) makes this threat much greater.

Table 4.1. Some estimates of Preweaning mortality in goats

Ecozone	Country	Breed	Management	Age class	Mortality*		Author(s)
					% ANB	% TDTH
Highlands	Rwanda	Rwandan	Station	0-5 m	26.30	--	Murayi et al., 1987
Humid	Ghana	WAD	Station	0-3 m	--	75.8	Dankwa, 1976
Humid	Ghana	WAD	Station	Preweaning		78	Yebuah, 1975 cited in Dankwa,
Humid	Nigeria	French Alpin WAD	Station	0-3 m	28.57	--	Nwodi, 1979
Humid	Nigeria	French Alpin WAD	Station	0-5 m	52.38	--	Nwodi, 1979
Humid	Nigeria	WAD	Station	0-3 m	38.6	--	Osuagwuh & Akpokodje, 1981
Humid	Nigeria	WAD	Station	Preweaning	32.5	--	Ngere et al., 1984
Humid	Nigeria	WAD	Station	Preweaning	39.6	--	Osuagwuh, 1985
Humid	Nigeria	WAD	Village	0-3 m	33	--	Mack, 1983
Humid	Nigeria	WAD	Village	0-3 m	19.6	27.79	Mosi et al., 1982
Humid	Nigeria	WAD	Village	0-3 m	25.6	--	Opasina, 1985
Humid	Nigeria	WAD	Village	0-5 m	23	--	Wilson, 1984
Sub-humid	Tanzania Newala	Village	0-3 m	43.5		--	Hendy, 1980
Sub-humid	Tanzania	Tanzanian	Station	0-4 m	23	--	Kyomo, 1978
Sub-humid	Nigeria	Maradi	Station	Preweaning	41.5	--	Ngere et al., 1984
Sub-humid	Ghana	WAD	Station	0-3 m	55	72.10	Oppong & Yebuah, 1981
Sub-humid	Nigeria	Maradi	Station	0-3 m	30.80	--	Adu et al., 1979
Sub-humid	Nigeria	Maradi	Village	Preweaning	32.80	--	Otchere et al., 1987
Sub-humid	Nigeria	WAD	Village	0-3 m	35	--	Bayer, 1982
Sub-humid	Kenya	Boer x East Africa	Station		18.6	--	Angwenyi and Bebe, 1989
Semi-arid	Kenya	Small East African	Village	0-5 m	22.3	--	Wilson, 1984
Semi-arid	Kenya	Small East African	Village	0-5 m	31.30	--	Wilson et al., 1984
Semi-arid	Mali	Sahel	Village	0-5 m	35	--	Wilson et al., 1984
Semi-arid	Mali	Sahel	Village	0-5 m	34.6	--	Wilson, 1984
Semi-arid	Sudan	Nubian	Station	0-4 m	43	--	El-Naim, 1979
Semi-arid	Sudan	Sudan Desert	Village	0-5 m	24.8	--	Wilson, 1984
Semi-arid	Zimbabwe	Boer x Indigenous	Station	0-5 m	14.90	--	Khombe, 1985
Semi-arid	Niger	Maradi	Station	0-4 m	29.5	--	Djibrillou, 1987
Semi-arid	Chad	Sahel	Village	Preweaning	15	--	Charray et al., 1980
Semi-arid	Somalia	White Somali	Village	0-4 m	24	--	Bouzat et al., 1992

* ANB = Animal born
* TDTH = Total death

Table 4.2. Some estimates of preweaning mortality in sheep

Ecozone	Country	Breed	Management	Age class	Mortality (%)		Authors
					ANB	TDTH
Highlands	Rwanda	East African long-fat-tailed	Station	0-5 m	17.5	--	Murayi et al., 1985
Highlands	Rwanda	East African long-fat-tailed	Station	0-5 m	13.6	--	Murayi et al, 1985
Humid	Côte d'Ivoire	WAD	Station	Preweaning	10	--	Ginistry, 1977
Humid	Ghana	WAD	Station	0-3 m	--	47.89	Dankwa, 1976
Humid	Ghana	WAD	Station	0-3 m	--	32.1-1	Oppong, 1973
Humid	Ghana	WAD	Station	0-4 m	--	20.95	Tuah & Baah, 1985
Humid	Nigeria	WAD	Station	0-3 m	20	--	Dettmers et al., 1976
Humid	Nigeria	WAD	Station	0-3 m	--	18.81	Otesile et al., 1982
Humid	Nigeria	WAD	Station	0-3 m		18	Taiwo et al., 1982
Humid	Nigeria	WAD	Village	0-3 m	16	--	Mack, 1983
Humid	Nigeria	WAD	Station	0-3 m	--	20	Dettmers and Loosli, 1974
Humid	Nigeria	WAD	Station	0-3 m	--	21.30	Dettmers et al., 1976
Humid	Senegal	WAD	Station	0-4 m	33.09	--	Fall et al., 1983
Humid	Senegal	WAD	Village	0-3 m	16	--	Faugère et al., 1988
Humid	Senegal	WAD	Station	0-4 m	33	--	Mbaye, 1983
Semi-arid	Mali	Sahel type	Village	0-5 m	30.29	--	Wilson, 1983
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m	--	46.6	Suleiman, 1976
Semi-arid	Zimbabwe	Indigenous x Merino	Station	0-5 m	13 1	--	Khombe, 1985
Semi-arid	Kenya	Masai	Village	0-5 m	32.1	--	Wilson et al., 1985
Semi-arid	Senegal	Peul	Station	0-4 m	27.85	--	Sow et al., 1988
Semi-arid	Senegal	Warale	Station	0-4 m	14.15	--	Sow et al., 1988
Semi-arid	Chad	Mayo Kebbi & Kirdi	Station	0-3 m	25.1	--	Guérin, 1979
Semi-arid	Senegal	Peul	Station	0-4 m	19.6	--	Sow et al., 1988
Semi-arid	Somali	Black-headed Somali	Village	0-4 m	26	--	Bouzat et al., 1992
Sub-humid	Nigeria	Uda	Station	Preweaning	44	--	Adu & Brinckman, 1978 cited in Osuagwuh, 1985
Sub-humid	Nigeria	Yankassa	Station	Preweaning	28	--	Adu & Buvanendra, 1978 cited in Osuagwuh, 1985
Sub-humid	Nigeria	Yankassa	Village	Preweaning	32.7	--	Otchere et al., 1987
Sub-humid	Togo	WAD	Station	0-4 m	29.76	--	Abassa & Adeshola-Ishola, 1988
Sub-humid	Zimbabwe	Merico & Dorper	Station	0-4 m	15.42	--	McKenzie & Grant, 1976
Sub-humid	Nigeria	Native	Station	0-3 m	24	--	Adu & Buvanendra, 1982

Table 4.3: Cause of preweaning mortality in goats

Ecozone	Country	Breed	Management	Age class	Cause		Author	Mortality
					Secondary	Main		PCTDTH	PCTANMCL
Humid	Cameroon	Native	Village	0-4 m	Died* 0-1 m		Ndamukong, 1985	4.5
Humid	Cameroon	Native	Village	0-4 m	Died* 1-2 m		Ndamukong, 1985	31.78
Humid	Cameroon	Native	Village	0-4 m	Died* 2-3 m		Ndamukong, 1985	45.43
Humid	Cameroon	Native	Village	0-4 m	Died* 3-4 m		Ndamukong, 1985	18.14
Humid	Nigeria	French Alpine x WAD	Station	0-5 m	Female		Nwodi, 1979		19.04
Humid	Nigeria	French Alpine x WAD	Station	0-5 m	Male		Nwodi, 1979		33.33
Humid	Nigeria	WAD	Station	0-4 m		Coccidiosis	Otesile et al., 1983	3.4
Humid	Nigeria	WAD	Station	0-4 m		Pneumonia	Otesile et al., 1983	15.9
Humid	Nigeria	WAD	Station	0-4 m		Helminthiasis	Otesile et al., 1983	6.24
Humid	Nigeria	WAD	Station	0-4 m		Bacterial Enteritis	Otesile et al., 1983	10.22
Humid	Nigeria	WAD	Station	0-3 m	RS	Coccidiosis	Osuagwuh & Akpokodje, 1981	1.5
Humid	Nigeria	WAD	Station	0-3 m	DS	Disease	Osuagwnh & Akpokodje, 1981	17.8
Humid	Nigeria	WAD	Station	0-3 m -	RS	Disease	Osuagwuh & Akpokodje, 1981	82.1
Humid	Nigeria	WAD	Station	0-3 m		Enteritis	Osuagwuh & Akpokodje, 1981	6
Humid	Nigeria	WAD	Station	0-3 m	Female		Osuagwuh & Akpokodje, 1981	32.8
Humid	Nigeria	WAD	Station	0-3 m	Male		Osuagwuh & Akpokodje, 1981	20.6
Humid	Nigeria	WAD	Station	0-3 m		Helminthiasis	Osuagwuh & Akpokodje, 1981	14.9
Humid	Nigeria	WAD	Station	0-3 m		PPR	Osuagwuh & Akpokodje, 1981	34.4
Humid	Nigeria	WAD	Station	0-3 m	DS	PPR	Osuagwuh & Akpokodje, 1981	3
Humid	Nigeria	WAD	Station	0-3 m	RS	PPR	Osuagwuh & Akpokodje, 1981	31.3
Humid	Nigeria	WAD	Station	0-3 m	Parity 1		Osuagwuh & Akpokodje, 1981		31.6
Humid	Nigeria	WAD	Station	0-3 m	Parity 2		Osuagwuh & Akpokodje, 1981		25
Humid	Nigeria	WAD	Station	0-3 m	Parity 3		Osuagwuh & Akpokodje, 1981		35.2
Humid	Nigeria	WAD	Station	0-3 m	Parity 4		Osuagwuh & Akpokodje, 1981		38.9
Humid	Nigeria	WAD	Station	0-3 m	Parity 5		Osuagwuh & Akpokodje, 1981		42.9
Humid	Nigeria	WAD	Station	0-3 m	Parity 6		Osuagwuh & Akpokodje, 1981		43.3
Humid	Nigeria	WAD	Station	0-3 m	Parity 7		Osuagwuh & Akpokodje, 1981		50
Humid	Nigeria	WAD	Station	0-3 m	Parity 8		Osuagwuh & Akpokodje, 1981		52.6
Humid	Nigeria	WAD	Station	0-3 m		Pneumonia	Osuagwuh & Akpokodje, 1981	31.3
Humid	Nigeria	WAD	Station	0-3 m	DS	Pneumonia	Osuagwuh & Akpokodje, 1981	11.9
Humid	Nigeria	WAD	Station	0-3 m	RS	Pneumonia	Osuagwuh & Akpokodje, 1981	19.4
Humid	Nigeria	WAD	Station	0-3 m	Single		Osuagwuh & Akpokodje, 1981	19.51
Humid	Nigeria	WAD	Station	0-3 m		Starvation Malnutrition	Osuagwuh & Akpokodje, 1981	12
Humid	Nigeria	WAD	Station	0-3 m	DS	Starvation Malnutrition	Osuagwuh & Akpokodje, 1981	3
Humid	Nigeria	WAD	Station	0-3 m	RS	Starvation Malnutrition	Osuagwuh & Akpokodje, 1981	9
Humid	Nigeria	WAD	Station	0-3 m	Triplet		Osuagwuh & Akpokodje, 1981	27.64
Humid	Nigeria	WAD	Station	0-3 m	Twin		Osuagwuh & Akpokodje, 1981	52.84
Humid	Nigeria	WAD	Village	0-3 m	Female		Opasina, 1985		16.7
Humid	Nigeria	WAD	Village	0-3 m	Male		Opasina, 1985		33.3
Humid	Nigeria	WAD	Village	0-4 m	PPR		Opasina, 1983		5
Semi-arid	Kenya	Small EA	Station	Preweaning	Single & kidding beginning long DS		Rutagwenda et al., 1985		54
Semi-arid	Kenya	Small EA	Station	Preweaning	Single & kidding prior to SR		Rutagwenda et al., 1985		30
Semi-arid	Kenya	Small EA	Station	Preweaning	Single & kidding at the onset of the LR		Rutagwenda et al., 1985		0
Semi-arid	Kenya	Small EA	Station	Preweaning	Twin & kidding beginning long DS		Rutagwenda et al., 1985		80
Semi-arid	Kenya	Small EA	Station	Preweaning	Twin & kidding during short DS		Rutagwenda et al., 1985		64
Semi-arid	Kenya	Small EA	Station	Preweaning	Twin & kidding at the onset of LR		Rutagwenda et al., 1985		0
Semi-arid	Kenya	Small EA	Station	Preweaning	Twin & kidding prior to SR		Rutagwenda et al., 1985		62
Semi-arid	Kenya	Small EA	Village	0-5 m		Disease	Peacock, 1982	31
Semi-arid	Kenya	Small EA	Village	0-5 m		Disease	Wilson et al., 1984	31.3
Semi-arid	Kenya	Small EA	Village	0-5 m	Female		Wilson et al., 1984		23
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 1		Wilson et al., 1985		24.8
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 2		Wilson et al., 1985		19.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 3		Wilson et al., 1985		48.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 4		Wilson et al., 1985		45
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 5		Wilson et al., 1985		32.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 6		Wilson et al., 1985		20.2
Semi-arid	Kenya	Small EA	Village	0-5 m	Flock 7		Wilson et al., 1985		17.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Long DS		Peacock, 1982		31.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Long DS		Wilson et al., 1984		31.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Long DS		Wilson et al., 1985		40.6
Semi-arid	Kenya	Small EA	Village	0-5 m	Long RS		Peacock, 1982		14.6
Semi-arid	Kenya	Small EA	Village	0-5 m	Long RS		Wilson et al., 1984		14.6
Semi-arid	Kenya	Small EA	Village	0-5 m	Long RS		Wilson et al., 1985		17.5
Semi-arid	Kenya	Small EA	Village	0-5 m		Lost	Peacock, 1982	9
Semi-arid	Kenya	Small EA	Village	0-5 m	Male		Wilson et al., 1984		21.7
Semi-arid	Kenya	Small EA	Village	0-5 m		Malnutrition	Peacock, 1982	6.9
Semi-arid	Kenya	Small EA	Village	0-5 m		Malnutrition	Wilson et al., 1984	7
Semi-arid	Kenya	Small EA	Village	0-5 m	Parity 1		Wilson et al., 1984		23.6
Semi-arid	Kenya	Small EA	Village	0-5 m	Parity 2		Wilson et al., 1984		20
Semi-arid	Kenya	Small EA	Village	0-5 m	Parity 3		Wilson et al., 1984		13
Semi-arid	Kenya	Small EA	Village	0-5 m		Predator	Peacock, 1982	8.3
Semi-arid	Kenya	Small EA	Village	0-5 m		Predator	Wilson et al., 1984	8
Semi-arid	Kenya	Small EA	Viliage	0-5 m	Short DS		Peacock, 1982		23.8
Semi-arid	Kenya	Small EA	Village	0-5 m	Short DS		Wilson et al., 1984		23.8
Semi-arid	Kenya	Small EA	Village	0-5 m	Short DS		Wilson et al., 1985		25.5
Semi-arid	Kenya	Small EA	Village	0-5 m	Short DS		Peacock, 1982		19.3
Semi-arid	Kenya	Small EA	Village	0-5 m	Short RS		Wilson et al., 1984		19.3
Semi-arid	Kenya	Small EA	Village	0-5 m	Short RS		Wilson et al., 1985		34.4
Semi-arid	Kenya	Small EA	Village	0-5 m	Single		Peacock, 1982		18.8
Semi-arid	Kenya	Small EA	Village	0-5 m	Single		Wilson et al., 1984		18.8
Semi-arid	Kenya	Small EA	Village	0-5 m	Single		Wilson et al., 1985		21.3
Semi-arid	Kenya	Small EA	Village	0-5 m	Twin		Wilson et al., 1984		25.8
Semi-arid	Kenya	Small EA	Village	0-5 m	Twin		Wilson et al., 1985		37.7
Semi-arid	Kenya	Small EA	Village	0-5 m		Unknown	Wilson et al., 1984	44.4
Semi-arid	Mali	Sahel	Village	0-5 m	Cold DS		Wilson et al., 1984		39.5
Semi-arid	Mali	Sahel	Village	0-5 m		Diarrhoea	Traore, 1985	11.67
Semi-arid	Mali	Sahel	Village	0-5 m	Dry cool SB		Wilson, 1983		35.66
Semi-arid	Mali	Sahel	Village	0-5 m	Dry hot SB		Wilson, 1983		27.8
Semi-arid	Mali	Sahel	Village	0-5 m	Male		Wilson et al., 1984		32.9
Semi-arid	Mali	Sahel	Village	0-5 m	Female		Wilson et al., 1984		37
Semi-arid	Mali	Sahel	Village	0-5 m	Hot DS		Wilson et al., 1984		36.7
Semi-arid	Mali	Sahel	Village	0-5 m	RS		Wilson et al., 1984		32.5
Semi-arid	Mali	Sahel	Village	0-5 m	Millet field		Wilson, 1983		39.11
Semi-arid	Mali	Sahel	Village	0-5 m		Others	Traore, 1985	18.33
Semi-arid	Mali	Sahel	Village	0-5 m	Parity 1		Wilson et al., 1984		47.9
Semi-arid	Mali	Sahel	Village	0-5 m	Parity 2		Wilson et al., 1984		38.8
Semi-arid	Mali	Sahel	Village	0-5 m	Parity 3		Wilson et al., 1984		31.4
Semi-arid	Mali	Sahel	Village	0-5 m		Pneumopathies	Traore, 1985	51.8
Semi-arid	Mali	Sahel	Village	0-5 m	Post RSB		Wilson, 1983		36.63
Semi-arid	Mali	Sahel	Village	0-5 m	Post RS		Wilson et al., 1984		30.9
Semi-arid	Mali	Sahel	Village	0-5 m	RS		Wilson et al., 1984		32.5
Semi-arid	Mali	Sahel	Village	0-5 m	RSB		Wilson, 1983		38.27
Semi-arid	Mali	Sahel	Village	0-5 m	Rice field		Wilson, 1983		30.07
Semi-arid	Mali	Sahel	Village	0-5 m	Single		Wilson et al., 1984		33.3
Semi-arid	Mali	Sahel	Village	0-5 m	Single		Wilson, 1983		23.54
Semi-arid	Mali	Sahel	Village	0-5 m	Triplet		Wilson, 1983		48.47
Semi-arid	Mali	Sahel	Village	0-5 m	Twin		Wilson et al., 1984		36.6
Semi-arid	Mali	Sahel	Village	0-5 m	Twin		Wilson, 1983	.	31.76
Semi-arid	Mali	Sahel	Village	0-5 m		Unknown	Traore, 1985	18.33
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Cold DS		Wilson et al., 1984		21.3
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Female		Wilson et al., 1984		21.9
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Hot DS		Wilson et al., 1984		34
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Male		Wilson et al., 1984		27.7
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Migratory		Wilson et al., 1984		25.5
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Parity 1		Wilson et al., 1984		43.7
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Parity 2		Wilson et al., 1984		21.6
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Parity 3		Wilson et al., 1984		12.3
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Post RS		Wilson et al., 1984		27
Semi-arid	Sudan	Sudan desert	Village	0-5 m	RS		Wilson et al., 1984		16.9
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Sedentary		Wilson et al., 1984		24.1
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Single		Wilson et al., 1984		26
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Triplet		Wilson et al., 1984		26.3
Semi-arid	Sudan	Sudan desert	Village	0-5 m	Twin		Wilson et al., 1984		22.1
Sub-humid	Ghana	WAD	Station	0-3 m		Monieziasis	Oppong & Yebuah, 1981	9.24
Sub-humid	Ghana	WAD	Station	0-3 m		Others	Oppong & Yebuah, 1981	11.5
Sub-humid	Ghana	WAD	Station	0-3 m		PGE	Oppong & Yebuah, 1981	2.05
Sub-humid	Ghana	WAD	Station	0-3 m		Pneumonia	Oppong & Yebuah,	27.92
Sub-humid	Ghana	WAD	Station	0-3 m		Starvation	Oppong & Yebuah, 1981	16.02
Sub-humid	Ghana	WAD	Station	0-3 m		Unknown	Oppong & Yebuah, 1981	5.33
Sub-humid	Tanzania	Newala	Village	0-3 m	Female		Hendy, 1980		44
Sub-humid	Tanzania	Newala	Village	0-3 m	Male		Hendy, 1980		43
Sub-humid	Tanzania	Tanzanian	Station	0-4 m		Accident	Kyomo, 1978	8
Sub-humid	Tanzania	Tanzanian	Station	0-4 m		Enteritis	Kyomo, 1978	3.5
Sub-humid	Tanzania	Tanzanian	Station	0-4 m		General weakness	Kyomo, 1978	64.8
Sub-humid	Tanzania	Tanzanian	Station	0-4 m		Plant poisonning	Kyomo, 1978	2
Sub-humid	Tanzania	Tanzanian	Station	0-4 m		Pneumonia	Kyomo, 1978	19.1
Sub-humid	Tanzania	Tanzanian	Station	0-4 m		Septicaemia	Kyomo, 1978	0.5

* Specified period in which a given proportion of preweaning death occurred. Such a period can be a predisposing factor that influences the effect of the main cause of death.

DS Dry Season
RS Rainy Season
SR Short Rains
LR Long Rains
SB Season of Birth
RSB Born in Rainy Season
PCTDTH Per cent Total Death
PCTANCL Per cent Animals in the Class

Table 4.4. Causes of preweaning mortality in sheep

Ecozone	Country	Breed	Management	Age class	Cause		Author	Mortality
					Secondary	Main		PCTDTHCL	PCTANMCL
Humid	Cameroon	Native	Village	0-4 m	Died 0-1 m*		Ndamukong, 1985	76.42
Humid	Cameroon	Native	Village	0-4 m	Died 1-2 m*		Ndamukong, 1985	5.92
Humid	Cameroon	Native	Village	0-4 m	Died 2-3 m*		Ndamukong, 1985	8.83
Humid	Cameroon	Native	Village	0-4 m	Died 3-4 m		Ndamukong, 1985	8.83
Humid	Cote d'Ivoire	WAD	Village	0-5 m	BW 1-1.5 kg		Rombaut & Vlaenderen 1976		80
Humid	Cote d'Ivoire	WAD	Village	0-5 m	BW < 1 kg		Rombaut & Vlaenderen 1976		100
Humid	Ethiopia	Menz	Village	0-5 m	Died 0-1 d*		Wilson et al., 1985	35.6
Humid	Ethiopia	Menz	Village	0-5 m	Died 0-1 m*		Wilson et al., 1985	67.8
Humid	Ethiopia	Menz	Village	0-5 m	Died 1-7 d*		Wilson et al., 1985	22
Humid	Ethiopia	Menz	Village	0-5 m	Died 2-3 m*		Wilson et al., 1985	18.6
Humid	Ethiopia	Menz	Village	0-5 m	Died 3-5 m*		Wilson et al., 1985	13.6
Humid	Ethiopia	Menz	Village	0-5 m	Died 7-30 d*		Wilson et al., 1985	10.2
Humid	Ghana	WAD	Station	0-4 m	DS		Tuah & Baah, 1985		22.6
Humid	Ghana	WAD	Station	0-3 m		Enterotoxemia	Dankwa, 1976	2.20
Humid	Ghana	WAD	Station	0-3 m		Haemonchosis	Dankwa, 1976	1.32
Humid	Ghana	WAD	Station	0-3 m		Heartwater	Dankwa, 1976	3.53
Humid	Ghana	WAD	Station	0-4 m	Major rains		Tuah & Baah, 1985		27.1
Humid	Ghana	WAD	Station	0-4 m	Minor rains		Tuah & Baah, 1985		21.8
Humid	Ghana	WAD	Station	0-3 m		PGE	Dankwa, 1976	15.45
Humid	Ghana	WAD	Station	0-3 m		Plant poisoning	Dankwa, 1976	5.74
Humid	Ghana	WAD	Station	0-3 m		Pneumopathies	Dankwa, 1976	30.02
Humid	Ghana	WAD	Station	0-4 m	Single		Tuah & Baah, 1985		7.48
Humid	Ghana	WAD	Station	0-3 m		Snake bite	Dankwa, 1976	1.10
Humid	Ghana	WAD	Station	0-3 m		Starvation	Dankwa, 1976	9.5
Humid	Ghana	WAD	Station	0-3 m		Tapeworms	Dankwa, 1976	6.18
Humid	Ghana	WAD	Station	0-4 m	Twin		Tuah & Baah, 1985		13.47
Humid	Nigeria	Uda x WAD	Station	0-3 m	Early DS		Taiwo et al., 1982		50
Humid	Nigeria	Uda x WAD	Station	0-3 m	Early RS		Taiwo et al., 1982		0
Humid	Nigeria	WAD	Station	0-3 m		Coccidiosis	Otesile et al., 1982	1.56
Humid	Nigeria	WAD	Station	0-3 m	Early DS		Taiwo et al., 1982		35
Humid	Nigeria	WAD	Station	0-3 m	Early RS		Taiwo et al., 1982		5
Humid	Nigeria	WAD	Station	0-3 m		Enterotoxemia	Otesile et al, 1982	0.6
Humid	Nigeria	WAD	Station	0-3 m	Female		Dettmers et al., 1976		21.05
Humid	Nigeria	WAD	Station	0-3 m		Haemonchosis	Otesile et al., 1982	3.13
Humid	Nigeria	WAD	Station	0-3 m	Male		Dettmers et al., 1976		17.72
Humid	Nigeria	WAD	Station	0-3 m		PPR	Otesile et al., 1982	2.82
Humid	Nigeria	WAD	Station	0-3 m		Pneumonia	Otesile et al., 1982	6
Humid	Nigeria	WAD	Station	0-3 m		Septicaemia	Otesile et al., 1982	0.6
Humid	Nigeria	WAD	Station	0-3 m	Single		Dettmers et al., 1976		14.75
Humid	Nigeria	WAD	Station	0-3 m		Starvation	Otesile et al., 1982	0.6
Humid	Nigeria	WAD	Station	0-3 m		Taeniasis	Otesile et al., 1982	1.56
Humid	Nigeria	WAD	Station	0-3 m	Triplet		Dettmers et al., 1976		40.75
Humid	Nigeria	WAD	Station	0-3 m	Twin		Dettmers et al., 1976		18.92
Humid	Nigeria	Yankasa x WAD	Station	0-3 m	Early DS		Taiwo et al., 1982		40
Humid	Nigeria	Yankasa x WAD	Station	0-3 m	Early RS		Taiwo et al., 1982		0
Humid	Senegal	WAD	Station	0-4 m	Female		Fall et al., 1983		33.22
Humid	Senegal	WAD	Station	0-4 m	Male		Fall et al., 1983		32.96
Humid	Senegal	WAD	Station	0-4 m	Parity 1		Fall et al., 1983		54.48
Humid	Senegal	WAD	Station	0-4 m	Parity 2		Fall et al., 1983		34.05
Humid	Senegal	WAD	Station	0-4 m	Parity 3		Fall et al., 1983		19.34
Humid	Senegal	WAD	Station	0-4 m	Single		Fall et al., 1983		27.67
Humid	Senegal	WAD	Station	0-4 m	Twin		Fall et al., 1983		38.51
Semi-arid	Kenya	Masai	Village	0-5 m		Disease	Peacock, 1982		17
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 1		Wilson et al., 1985		36.7
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 2		Wilson et al., 1985		36.8
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 3		Wilson et al., 1985		31.5
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 4		Wilson et al., 1985		33
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 5		Wilson et al., 1985		40.9
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 6		Wilson et al., 1985		26 4
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 7		Wilson et al. 1985		32.4
Semi-arid	Kenya	Masai	Village	0-5 m	Flock 8		Wilson et al., 1985		25.1
Semi-arid	Kenya	Masai	Village	0-5 m	Long DS		Peacock, 1982		22.4
Semi-arid	Kenya	Masai	Village	0-5 m	Long DS		Wilson et al., 1985		38.1
Semi-arid	Kenya	Masai	Village	0-5 m	Long RS		Peacock, 1982		13.9
Semi-arid	Kenya	Masai	Village	0-5 m	Long RS		Wilson et al., 1985		27.3
Semi-arid	Kenya	Masai	Village	0-5 m		Lost	Peacock, 1982	15
Semi-arid	Kenya	Masai	Village	0-5 m		Malnutrition	Peacock, 1982	2
Semi-arid	Kenya	Masai	Village	0-5 m		Predator	Peacock, 1982	25
Semi-arid	Kenya	Masai	Village	0-5 m	Short DS		Peacock, 1982		17.2
Semi-arid	Kenya	Masai	Village	0-5 m	Short DS		Wilson et al., 1985		27.3
Semi-arid	Kenya	Masai	Village	0-5 m	Short RS		Peacock, 1982		22.6
Semi-arid	Kenya	Masai	Village	0-5 m	Short RS		Wilson et al., 1985		35.7
Semi-arid	Kenya	Masai	Village	0-5 m	Single		Peacock, 1982		7.7
Semi-arid	Kenya	Masai	Village	0-5 m	Single		Wilson et al., 1985		14.4
Semi-arid	Kenya	Masai	Village	0-5 m	Twin		Peacock, 1982		31.4
Semi-arid	Kenya	Masai	Village	0-5 m	Twin		Wilson et al., 1985		49.8
Semi-arid	Kenya	Sahel	Village	0-5 m	Dry cool SB		Wilson, 1983		31.36
Semi-arid	Kenya	Sahel	Village	0-5 m	Dry hot SB		Wilson, 1983		23.50
Semi-arid	Kenya	Sahel	Village	0-5 m		Gastroenteritis	Traore, 1985	8.3
Semi-arid	Mali	Sahel	Village	0-5 m		General weakness	Traore, 1985	23.33
Semi-arid	Mali	Sahel	Village	0-5 m	Millet field		Wilson, 1983		34.81
Semi-arid	Mali	Sahel	Village	0-5 m		POX	Traore, 1985	34
Semi-arid	Mali	Sahel	Village	0-5 m		Pneumopathies	Traore, 1985	10
Semi-arid	Mali	Sahel	Village	0-5 m	Post RSB		Wilson, 1983		32.33
Semi-arid	Mali	Sahel	Village	0-5 m	RSB		Wilson, 1983		33.97
Semi-arid	I Mali	Sahel	Village	0-5 m	Rice field		Wilson 1983		25.77
Semi-arid	Mali	Sahel	Village	0-5 m	Single		Wilson, 1983		19.24
Semi-arid	Mali	Sahel	Village	0-5 m	Triplet		Wilson, 1983		44.17
Semi-arid	Mali	Sahel	Village	0-5 m	Twin		Wilson, 1983		27.46
Semi-arid	Mali	Sahel	Village	0-5 m		Unknown	Traore, 1985	20
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m	BW =1.8-2.7 kg		Suleiman, 1976	49.16
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m	BW = 2.8-3.6 kg		Suleiman, 1976	27.5
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m	BW = 3.7-4.5 kg		Suleiman, 1976	20.83
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m	BW = >4.6 kg		Suleiman, 1976	2.5
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m		General weakness	Suleiman, 1976	35
Semi-arid	Sudan	Sugor & Burog	Station	0-4 m	Others		Suleiman, 1976	5
Semi-arid	Sudan	Sugor & Burog	Station	04 m		Pneumonia	Suleiman, 1976	60
Semi-arid	Ghana	WAD	Station	0-3 m		Chemical poisoning	Oppong, 1973	0.8
Sub-humid	Ghana	WAD	Station	0-3 m		Enterotoxemia	Oppong, 1973	0.64
Sub-humid	Ghana	WAD	Station	0-3 m		Heartwater	Oppong, 1973	0.43
Sub-humid	Ghana	WAD	Station	0-3 m		PGE	Oppong, 1973	3.01
Sub-humid	Ghana	WAD	Station	0-3 m		Pneumonia	Oppong, 1973	14
Sub-humid	Ghana	WAD	Station	0-3 m		Tapeworms	Oppong, 1973	10.12
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m		Mis-mothering/starvation	McKenzie & Grant, 1976	11.6
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m		Complicated exposure	McKenzie & Grant, 1976	21.6
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m	Twin	Malnutrition	McKenzie & Grant,	13.3
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m		Pneumopathies (ID)	McKenzie & Grant, 1976	6.6
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m		Disease - general	McKenzie & Grant, 1976	20
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m	Management		McKenzie & Grant,	70
Sub-humid	Zimbabwe	Merino & Dorper	Station	0-4 m	Twin		McKenzie & Grant, 1976	89
Sub-humid	Mali	Sahel	Village	0-5 m	Part.lnt. > 215 d		Wilson, 1983	25

* Specified period in which a given proportion of preweaning death occurred. Such a period can be a predisposing factor that influences the effect of the main cause of death.

SB Season of Birth
RSB Born in Rainy Season
ID Infectious Disease.
PCTDTH Per cent Total Death
PCTANCL Per cent Animals in the Class

References for chapter IV

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